1. Field of the Invention
The invention relates to a laser-assisted milling process for machining high mechanical strength materials such as, for example, certain steels, titanium alloys, superalloys, and ceramics.
2. Summary of the Prior Art
Laser-assisted machining involves using a laser to heat a workpiece during machining so as to produce a temperature in the cutting zone sufficient to reduce the mechanical properties of the material of the workplace in the cutting zone and thereby facilitate the machining operation.
It is known to use laser assistance in turning operations on a lathe. In turning operations the workpieces are articles of revolution which are rotated, and the cutting tool comprises a single cutting plate which machines the workpiece continuously as the workpiece rotates. The laser is connected to the tool support so that the laser beam moves simultaneously with the cutting tool. The point where the laser beam impinges on the workpiece is therefore always in the same position relative to the cutting plate, and moves over the workpiece at the same speed and in the same direction as the cutting speed. The point of impingement of the laser beam is usually located on the chamfered edge of the cutting zone and disposed immediately in front of the cutting tool.
However, laser assistance is difficult when it is required to machine parallelepipedic workpieces by milling, because the milling tool usually comprises a number of cutting plates which operate on the workpiece in succession as the milling tool rotates. Machining is thus intermittent and it is difficult to heat the workpiece at the chamfered edge of the cutting zone immediately in front of each cutting plate. For such heating it is necessary to use a number of laser beams associated one with each of the cutting plates. Also, depending upon the geometry of the milling tool the dwell time of each laser beam may be too short.